Incandescent lamp



April 10, 1928. 1,665,799

A. B. SMITH INCANDES CENT LAMP Filed Oct. 28, 1925 2 Sheets-Sheet 1gwwnto'o rr/r/vsses q ARTHUR 8. 5M! TH AFT/l0? 0. 54 /771 April 10,1928. 1,665,799

' A. B. SMITH v INCANDESCENT LAMP Filed Oct. 28, 1925 2 Sheets-Sheet E[WWI E5655 amnion Patented Apr. 10, 1928.

UNITED STATES ARTHUR B. SMITH, OF SOUTH BROWNSVILLE, PENNSYLVANIA.

INCANDESCENT LAMP.

Application filed October 28, 1925. Serial No. 65,437.

The present invention relates to incandescent lamps.

The principal object of the present invention is to equip the filamentsupporting stem with suitable reflective material in order to augmentthe volume of the light ray.

A further object of the invention is to make the filament supportingstem hollow throughout and to apply a reflective material thereto inorder to eilect increased illumination notwithstanding the use ofstandard filaments made from carbon, tungsten, tantalum, etc.

A further object of the invention is to provide means for magnifying thelight ray emanating from the filament which is adaptable for use inelectric bulbs of standard construction mountable in a socket in theusual manner.

Other objects of the invention will be understood from the followingdescription taken in connection with the accon'ipanying drawings,wherein Fig. 1 is a longitudinal sectional view of an elongated type ofincandescent lamp embodying the present invention.

Fig. 2 is a cross sectional view taken on the line 22 of Fig. 1 lookingin the direction of the arrows;

Fig. 3 is a perspective view of a filament stem. constructed inaccordance with the present invention;

Fig. 4 is a longitudinal sectional view of a modification of the presentinvention; and

Fig. 5 is a sectional view taken on the line 5 5 of Fig. looking in thedirection of the arrows.

The form of invention illustrated in Figs. 1 to 3 consists of a base orplug 6 of substantially standard construction which is adapted forengagement in a socket in a manner well known in the art. A bulb 7 ofthe elongated type is mounted in the socket 6 and has concentricallyarranged therein a stem 8 constructed in accordance with the presentinvention. The base of the stem is preferably flared outwardly so as toprovide a bell shape terminal, as indicated at 9, which impinges againstthe bottom of the recess formed in the plug 6. At a point just beyondthe end of the plug from which the bulb 7 extends, the stem isthickened, as indicated at 10, in order to provide an annulus for apurpose hereinafter described. The stem is hollow throughout its lengthbut is closed at its outer end 11 and is thickened to provide a ring orannulus 12 similar to the annulus 10.

Leading in wires 13 extend from the base 6 in the usual manner andproject outwardly through the inner end of the stem 8. The outerterminals 01 these wires are engaged with a spider generally designated14 which in the. present instance consists of a series of supportinghooks, oi the type now used in the art, which radiate from the annulus10. The spider may be connected to the leading in wires by platinum orother suitable metal having a coeflicient of expansion equal to thecoeflicient of expansion ot the glass at a point where the wires extendthroughthe annulus 10. A similar spider generally designated 15 and alsocomprising a series of hooks, radiates from the annulus 12. The spiders14c and 15 are engaged by a filament 16 which may be composed of anymetal now used in the art in this capacity.

In order to magnify the volume of light ray emanating from the filamentI coat the inner surface of the stem 8 with a film of silver 17, which,as shown in Fig. 1, covers the entire interior of the stem. The stem is,

of course, made of plain, clear glass and, consequently, acts as amirror, for reflecting the light rays, in a manifest manner.

WVhei-e it is desired to use a round type of bulb it is generallypreferred to use a eomplemental stem structure in order to bring thelight reflector into closer proximity to the bulb. Consequently, inFigs. 4 and 5 of the d 'awings I have illustrated a round type of bulb,designated 7, which has mounted therein a stem 8. The inner end or baseof the stem is mounted in the base of the bulb in the san'ie manner asthe stem 8, but the outer end thereof is flared so that it is ofsubstantially elliptical contour in side elevation, as shown in Fig. 4and of substantially circular configuration in plan, as shown in Fig. 5.In this form of invention, the leading in wires 13 extend outwardlybeyond the outer terminal of the body portion of the stem in closeproximity to a mount 18 which issues from the outer end of the stem andhas its outer terminal thickened to provide an annulus 11'. The annulushas a spider 15 radiating therefrom which supports a cylinder 16. Thiscylinder is carried by the spider and has its terminals engaged with theleading in wires 13. The interior of the stem 8 is coated with a film ofsilver 17 this film extending outwardly into the mount 18, as shown bythe dotted lines in Fig. 4:- Consequently, the mirrored reflectingmedium herein employed is brought into as close proximity to thefilament as possible. It is apparent that the configuration of the stem8' and the.

manner of mounting the same in the bulb afiords a maximum reflectionfrom the filament.

From the above it is apparent that the principle of the presentinvention embodies associating a reflective medium with the filament inorder to augment the volume of light obtained without appreciablyincreasing the cost of the bulb because of the fact that the reflectingmeans forms a part of the stem whichis necessary to support thefilament. It is, of course, to be understood that various changes may bemade in this device with in the scope of the claim hereto appended.

What is claimed is An incandescent lamp of the character described,including a plug having a recess therein, comprising a bulb mounted insaid recess, a hollow filament supporting mem- 3'31, comprising acircular head having the upper surface thereof convexed and having theunder side drawn downwardly to provide a supporting stem of relativelysmall diameter and secured in said plug, a filament mount comprising ashort upstanding member arranged centrally upon the upper surface ofsaid head, means carried by said mount for supporting the filament inclose proximity to the head. and reflector means coatii'ig the interiorsurface of the head and stem.

lt'i': testimony whereof I aflix my signature.

ARTHUR B. SMITH.

